Measure humidity & temperature with Arduino

Arduino tutorial 5# how to Measure humidity & Temperature with DHT22/DHT11 in Arduino.

Posted 2 CommentsPosted in Arduino

Hi friends. In this tutorial we will see how to measure temperature & humidity with  DHT22/DHT11 in Arduino so lets get started. For this you will need

COMPONENTS:
  1. Arduino,
  2. jumper wire,
  3. breadboard,
  4. 10K ohms resistor,
  5. DHT22 sensor.

There are two version of sensor. One is DHT11 & second is DHT22.

DHT11 is cheaper in cost and less accurate compare to DHT22.

DHT22 is more accurate and have larger range compare to DHT11.

In this tutorial we are using DHT22. Sensor have four pin. Pin 1 is for : 5V power, Pin 2 is for: Data , Pin 3: not used, Pin 4 is for: GND.

CIRCUIT DIAGRAM:
Circuit diagram for DHT22 with arduino
Circuit diagram for DHT22 with arduino

This is circuit diagram. 10k ohms resistor is used which is a pull-up resistor because Random noise can change the state to go HIGH or LOW level randomly. So, The pull-up resistor ensures that the wire is at a defined logic level even if no active devices are connected to it. Do connection as shown in diagram.

Go to github website https://github.com/adafruit/DHT-sensor-library the link is mentioned below in the description. And download the file. After downloading unzip it. Change the file name to DHT.

Delete this file

Delete these files. shown in right side of image. And copy the DHT folder & paste in Arduino library folder. Now open the example folder then DHT tester. Open DHT tester file you can directly upload the sketch.

Sketch:
// Example testing sketch for various DHT humidity/temperature sensors
// Written by ladyada, public domain

#include "DHT.h"

#define DHTPIN 2     // what digital pin we're connected to

// Uncomment whatever type you're using!
//#define DHTTYPE DHT11   // DHT 11
#define DHTTYPE DHT22   // DHT 22  (AM2302), AM2321
//#define DHTTYPE DHT21   // DHT 21 (AM2301)

// Connect pin 1 (on the left) of the sensor to +5V
// NOTE: If using a board with 3.3V logic like an Arduino Due connect pin 1
// to 3.3V instead of 5V!
// Connect pin 2 of the sensor to whatever your DHTPIN is
// Connect pin 4 (on the right) of the sensor to GROUND
// Connect a 10K resistor from pin 2 (data) to pin 1 (power) of the sensor

// Initialize DHT sensor.
// Note that older versions of this library took an optional third parameter to
// tweak the timings for faster processors.  This parameter is no longer needed
// as the current DHT reading algorithm adjusts itself to work on faster procs.
DHT dht(DHTPIN, DHTTYPE);

void setup() {
  Serial.begin(9600);
  Serial.println("DHTxx test!");

  dht.begin();
}

void loop() {
  // Wait a few seconds between measurements.
  delay(2000);

  // Reading temperature or humidity takes about 250 milliseconds!
  // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
  float h = dht.readHumidity();
  // Read temperature as Celsius (the default)
  float t = dht.readTemperature();
  // Read temperature as Fahrenheit (isFahrenheit = true)
  float f = dht.readTemperature(true);

  // Check if any reads failed and exit early (to try again).
  if (isnan(h) || isnan(t) || isnan(f)) {
    Serial.println("Failed to read from DHT sensor!");
    return;
  }

  // Compute heat index in Fahrenheit (the default)
  float hif = dht.computeHeatIndex(f, h);
  // Compute heat index in Celsius (isFahreheit = false)
  float hic = dht.computeHeatIndex(t, h, false);

  Serial.print("Humidity: ");
  Serial.print(h);
  Serial.print(" %\t");
  Serial.print("Temperature: ");
  Serial.print(t);
  Serial.print(" *C ");
  Serial.print(f);
  Serial.print(" *F\t");
  Serial.print("Heat index: ");
  Serial.print(hic);
  Serial.print(" *C ");
  Serial.print(hif);
  Serial.println(" *F");
}
Explaination:

The purpose of the instruction “#include” is to include an external library in our project so we can use its functions. Define  DHT pin number that is pin 2. Define DHT type 22 or 11. Then initialize the library. Serial.begin (9600) it will create serial connection with Arduino. Serial.println will print hello massage when serial monitor is started. Dht.begin will start DHT. Lets going to loop function. We take measurement for humidity, temperature in Celsius & Fahrenheit using Float point h, t & f. “isnan” for  is not a number. This  is || OR Boolean operator.  If value of h,t or f is not a number it will print Failed to read from DHT sensor!. If you don’t want heat index you can delete it. Go to serial monitor now you can see the values of humidity, temperature in Celsius & Fahrenheit.

Components list to buy online:

http://amzn.to/2vqIKJP  (DHT22)

http://amzn.to/2fvSRJq   (Arduino)

http://amzn.to/2wxPmWz  (Breadboard)

http://amzn.to/2vJ3lvo   (Jumper wire)

http://amzn.to/2vmSK8l  (Resistor)

 

For more videos subscribe the channel

Till than keep learning keep making. 🙂

How to interface Photo-resistor with LED

Arduino tutorial 4# How to interface Photoresistor with LED

Posted Leave a commentPosted in Arduino

 

If you are visual guy you can watch this tutorial in video mention below this lesson.

In this tutorial we will see how to interface photo-resistor sensor with LED light. If you have not read my previous article for photo-resistor in Arduino. You can click here.

 

Interface LED with Photo-resistor circuit diagram
Interface LED with Photo-resistor circuit diagram

 

Do connection as shown in circuit diagram. Whenever light fall on sensor it will create high resistance and prevent to flow current. And LED light will OFF. When there is no light on sensor it will have less resistance and current will flow and LED will ON. All the parts and programming is same as previous video. Only for this you will need one LED light and 2 Extra jumper wire.

When I fall light on sensor LED light will OFF. When I move light from sensor it will again ON.

Components list for buying online.

http://amzn.to/2fvSRJq   (Arduino)

http://amzn.to/2vSpUON   (LED)

http://amzn.to/2uK49eW  (Photo-resistor)

http://amzn.to/2wxPmWz  (Breadboard)

http://amzn.to/2vJ3lvo   (Jumper wire)

http://amzn.to/2vmSK8l  (Resistor)

 

KEEP LEARNING KEEP MAKING 🙂

How to use photo-resistor with arduino

Arduino tutorial 3# How to use Photo-resistor with Arduino.

Posted 1 CommentPosted in Arduino

If you are visual guy you can watch this tutorial in video mention below this lesson.

In this tutorial we will see how to use photo-resistor in Arduino.

For this you will need

PART:
  1. Arduino,
  2. Jumper wire,
  3. breadboard,
  4. 10K ohms resistor,
  5. Photo-resistor.

A photo-resistor is a light-controlled variable resistor. The resistance of a photo-resistor decreases with increasing incident light intensity. An analog input converts a voltage level into a digital value.

Circuit Diagram :
Photo-Resistor with Arduino circuit Diagram
Photo-Resistor with Arduino circuit Diagram

In this circuit diagram we are using voltage divider. A voltage divider is a passive linear circuit that produces an output voltage that is a fraction of its input voltage. Here input voltage is 5V and two resistor are connected in series. One resistor which is fixed 10k ohms resistor. And other is photo resistor which is a light-controlled variable resistor. When light intensity changes the output voltage changes.

Assembly:
  1. Connect resistor as shown in diagram then connect photo-resistor.
  2. Make sure it is align in same column as shown in diagram.
  3. connect red wire to 5V socket on Arduino,  black wire to ground and green wire to A1.
  4. Upload the sketch below.
Sketch :
void setup() {
 Serial.begin(9600);
}

void loop() {
 int sensorvalue=analogRead(A1);
 Serial.println(sensorvalue);
 delay(100);
}
Explanation :

This is Serial.begin (9600) it will create serial connection with Arduino. By this Arduino can send text output. AnalogRead(A1) which will get reading from socket A1. And Store it to local integer value sensorvalue. So whatever A1 get output we will print it through serial.println(sensorvalue). “Println(sensorvalue)” will create sensor value in new line. If you use “serial.print(sensorvalue)” without “ln” it will print sensor value in the same line. Time delay is in millisecond which is time between each sensor value is printed.

Upload the sketch.

Go to tools and serial monitor. Now you can see values.

If I keep my finger it on sensor it will change value. So your values may be different because of lightning condition.

Components list to buy online:

http://amzn.to/2fvSRJq   (Arduino)

http://amzn.to/2uK49eW  (Photo-resistor)

http://amzn.to/2wxPmWz  (Breadboard)

http://amzn.to/2vJ3lvo   (Jumper wire)

http://amzn.to/2vmSK8l  (Resistor)

 keep learning keep making 🙂

How to fade on & off LED with Arduino

Arduino Tutorial 2# LED Light fade on and off.

Posted Leave a commentPosted in Arduino

If you are visual guy you can watch this tutorial in video mention below this lesson.

In this lesson we will see how to make LED light fade on and off. If you have learned my previous lesson 1 then you will have to change only sketch (programming).

All the parts, circuit diagram, assembly remain same as previous lesson LED blinking to see that click here.

After assembly you need to change sketch (programming). (more…)

Arduino Tutorial 1# LED Light blinking

Posted 1 CommentPosted in Arduino

If you are visual guy you can watch this tutorial in video mention below this lesson.

This is first lesson on arduino uno. In this lesson we will see how to make LED light blink using arduino. I will explain how you can change the blinking time with little change in programming (sketch). If you are very new to this just go to this Arduino official website and download IDE which is nothing but a software which will help you to write code and upload it to the board. (more…)